Control for multijet impulse turbine



Dec. 20, 1960 Filed May 8, 1959 B. R. NICHOLS CONTROL FOR MULTIJETIMPULSE TURBINE v 2 Sheets-Sheet 1 Dec- 20, 1960 B. R. NICHOLS 2,965,764

CONTROL FOR MULTIJET IMPULSE TURBINE Filed May 8, 1959 2 Sheets-Sheet 2&

NOZZLE CL 05/N6 United States Patent ()fiice 2,965,764 Patented Dec. 20,1960 CONTROL FOR MULTIJET IMPULSE TURBINE Beverly R. Nichols, Elm Grove,Wis., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis.

Filed May 8, 1959, Ser. No. 812,043

7 Claims. (Cl. 290-40) This invention relates to a hydraulic turbine ofthe impulse type which has a plurality of nozzles directing jets ofwater at buckets carried on the runner of the turbine, and particularlyto an arrangement for controlling the turbine. This application containssubject matter which is also disclosed in prior application S.N. 598,121of Beverly R. Nichols, filed July 16, 1956.

The development of impulse type hydraulic turbines began with a singlenozzle being provided to issue a single jet to rotate the impulserunner. When more power was needed, another runner was usually added tothe same shaft and another nozzle provided to rotate the second runner.The fact that such an arrangement required two runners rendered thisarrangement quite cost-1y. It had the further disadvantage of requiringconsiderably more space for the two runners than is required by a singlerunner. The modern solution to providing increased power is to provide aplurality of nozzles arranged around a single runner. Current designsutilize as many as six nozzles with a single runner. It has beendiscovered that impulse turbines having several nozzles required verysmall openings of each of the nozzles when the turbine is running underno load conditions. Thus when a hydraulic impulse turbine drivengenerator is started under no load and is being brought up tosynchronizing speed in preparation for connecting the generator to adistribution network, the openings of the nozzles are so small that theyhave become clogged or partially closed by silt and other foreign matterin the water passing through the nozzles. This makes it very difiicultfor the governor to maintain constant speed and to synchronize the unitin order to connect it to a distribution network.

The nature of the present invention, in a preferred embodiment, residesin providing a control system which will cause all but one of thenozzles to close when the turbine is operating under no load conditions.Thus with only one nozzle open and being used to synchronize the unit,that one nozzle will be opened sufficiently to permit foreign matter topass through the nozzle without clogging the nozzle. Thus it is aprimary object of the present invention to provide a control system foran impulse type hydraulic turbine which will provide for improvedcontrol of the turbine under no load conditions making it easier toachieve and maintain constant speed to synchronize the frequency of anattached generator to that of a distribution network when preparing toconnect the generator to the distribution network.

Another object of this invention is to provide a control system in whichoperation will shift from a single nozzle to all of the nozzlesautomatically when the load is placed upon the turbine.

Another object of this invention is to provide a control system thatwill automatically close all but one of the nozzles when load is takenfrom the turbine by having its generator disconnected from adistribution network.

Other objects and advantages will appear from the following descriptionconsidered in conjunction with the attached drawings in which:

Fig. 1 is a plan view of a turbine with certain parts in section showingthe nozzles, deflectors and the runner;

Fig. 2 is asimple diagram showing the manner in which an electricalgenerating unit is connected to the runner shown in Fig. 1; and

Fig. 3 is a schematic illustration of the system for controlling theoperation of the turbine according to this invention.

Referring to Fig. 1, there is disclosed an impulse type turbine having arunner 4 with buckets 2 mounted upon its periphery and upon which jetsof water impinge to rotate the runner 4. Runner 4 drives a shaft 6connected to rotate a generator 7 as shown in Fig. 2. Fluid enters theturbine assembly through a penstock 8 (Fig. 1) and the water is emittedby a plurality of nozzles 10.

Each nozzle 10 as shown in Figs. 1 and 3 has a movable needle 12 whichcontrols the size of an opening .14 in the nozzle. As shown in Fig. l, adeflector 16 is positioned adjacent each nozzle 10. Each deflector ispivotally movable into and out of a jet issued by a nozzle v10 tothereby rapidly deflect a portion of the jet. When it is necessary tovery rapidly reduce the amount of water impinging on the buckets 2, itis not always possible to close the opening 14 as rapidly as thecircumstances require. Rapid closing of the nozzle opening 14 can bevery dangerous because a shock wave resulting from the kinetic energy ofthe fluid would result and have a destructive eifect on the penstock 8.The purpose of each deflector 16 is to deflect a portion or all of thejet from the runner 4 to provide immediate control over the speed of theturbine While permitting needles 12 to close more slowly in response tochanges in speed of the turbine runner and thus prevent a shock wavefrom forming.

Speed responsive means (indicated generally by arrows 17, Fig. 3) areprovided to interpret and modify increases or decreases in the speed ofthe turbine runner 4 and generator 7 to provide movement which can beutilized to control the needles. The speed responsive means 17, however,are not powerful enough to move the plurality of needles. Individualsecondary power devices (indicated generally by the numeral 1 8) areprovided to move each of the needles. Individual connecting means(indicated generally by numeral 19) are provided to connect eachindividual power device 1 8 with the speed responsive means 17 so as tooperate each of the secondary power devices 18 in response to movementof the speed responsive means '17.

The speed responsive means 17 may comprise a governor arrangement(indicated generally by numeral 21) movable in response to increases ordecreases in the speed of the turbine runner 4 to thereby move thedeflectors 16, and a control means (indicated generally by numeral 23)to modify the movement caused by the governor arrangement to give theneedles the correct amount of movement for best efliciency.

The governor arrangement 21 comprises a motor 20 which is electricallyconnected by wires 22 to a permanent magnet generator (not shown)directly connected to the shaft of the turbine, so that the speed of themotor 20 will vary as the speed of the turbine runner. The con nectionof the motor 20 to the generator and the generator connection to theturbine is shown in U.S. Patent 2,106,- 684 issued to Joseph J. Ring,Beverly R. Nichols and Arnold Pfau, January 25, 1938. g

The operation of the governor arrangement will now be described. Themotor 20 rotates aflyb-all governor 24 which is connected to movablepiston 26 of main valve 28, to move the piston from a neutral positionto control a servomotor 30. Movable piston 26 controls a flow of fluidunder pressure from an inlet pipe 27 through main valve 28 in responseto increases or decreases in the speed of turbine runner 4, to move apiston 32 and a piston rod 34 in a desired direction. Any conventionaldevice (not shown) may be provided to return piston 26 to its neutralposition in a manner that is well known in the governor art.

Since deflectors 16 are provided adjacent the jets, means must beprovided to connect the deflectors with the governor arrangement.Referring to Fig. 3 the piston rod 34 of main servomotor 30 is pivotallyconnected to a link 38 which is fixed to deflector shaft 40 rotatablysupported in bearings 41. Deflector drive shaft 40 carries a double arm42 at its end. Pivotally connected to each end of the double arm 42 is acontrol link 44. Shaft 40, double arm 42 and control links 44 are shownin both Figs. 1 and 3. With further reference to Fig. 1, each controllink 44 is connected to an end 45 of a bell crank 46 which pivots abouta center point 48. Fixed to the center portion of each bell crank 46 isa deflector 16. An end 50 of each bell crank is connected to a link 52which is pivotally connected to an end 53 of a second bell crank 54which also carries a deflector 16. This provides an arrangement wherebythe six deflectors are rotated by a single deflector drive shaft 40 asshown in Fig. 1. The governor arrangement 21 rotates the deflector shaft40 which in turn causes deflector 16 to pivot into and out of theirassociated jets.

Control means 23 which modifies the movement caused by the governorarrangement 21 and which moves the connecting means 19 to operate theindividual secondary power devices 18, may comprise a primary powerdevice 73 operated by and connected to the governor arrangement, acontrol cam 84 rotated by the primary power device 73 and a cam shaft 86rotated by the control cam 84.

To operate the control means 23, the link 38 that is rotated by pistonrod 34 of the governor arrangement, is pivotally connected to a drivelink 66 which in turn is pivotally connected to one end of a bell crank68, which rotates about a pivot 70. The other end of bell crank 68 ispivot-ally connected at 71 to an intermediate portion of a floating link72. The floating link 72 operates the power device 73 which may comprisea control valve 78 and a control servomotor 80 operated by the controlvalve 78. End 74 of the floating link 72 is pivotally connected to apiston 76 of control valve 78. Raising or lowering the piston 76regulates a fiow of fluid under pressure from an inlet pipe 77 tooperate the control servomotor 80. Piston rod 82 of control servomotor80 is pivotally connected to the control cam 84 which rotates thecontrol shaft 86 rotatably supported by bearings 88.

Rotational movement of shaft 86 is relayed back to control valve 78 bymeans of a cam follower 90 rotatably mounted on floating link 72intermediate the end portions of the link. End 74 of the floating link72 is, as has been stated, connected to control valve 78. The other endof floating lever 72 (numbered 94) is connected to a spring 98 to urgethe cam follower 90 against the cam 84.

The operation of the primary power device 73 takes place in thefollowing described manner. Wit-h the piston '76 of control valve 78 inthe position shown in Fig. 3 shaft 86 will be held in a stationaryposition by control servomotor 80. A change in the speed of operation ofthe turbine wheel 4 will however cause the governor arrangement 21 toinitiate an action that Will drive link 66 to cause bell crank 68 torotate about pivot 70 and force floating link '72 to pivot about theroller 90 to either raise or lower piston 76 from the position shown inFig. 3. Control valve 78 will then admit fluid to one side of controlservomotor 80 to cause control cam 84 to rotate the shaft 86. Whencontrol cam '84 is rotated by the servomotor 80 cam follower will bemoved by cam 84 to cause the floating link 72 to now pivot about theconnection 71 in a direction opposite to the direction that the floatinglink was pivoted to actuate valve 78. This will move piston 76 back tothe position shown in Fig. 3 and stop the flow of fluid to the controlservomotor 80.

The individual secondary power devices 18 which are provided to moveeach needle may comprise a needle servomotor 102 and servomotoroperating equipment. As shown in Fig. 3, the servomotor 102 is operatedby fluid pressure admitted by a secondary control valve 104 having apiston 108 to control the fluid pressure from an inlet pipe 109 throughtubing 111 to the needle servomotor 102. Each individual secondary powerdevice 18 is operated by one of the individual connecting means 19 whichis moved by the rotation of control shaft 86.

Each individual connecting means 19 which connects an individualsecondary power device 18 to the control means 23 is the same except forthe manner in which the connecting means 19 is connected to therotatable shaft 86. For reasons that will be more fully discussed later,certain of the connecting means 19 are connected to the shaft 86 bymeans of control arms that are securely fastened to the shaft 86. Asshown in Fig. 3, however, the particular connecting means 19 that is i1-lustrated is connected to shaft 86 by a control arm 100a of specialdesign that will be described later in greater detail. Although themanner in which control means 23 operates arm 100a, difiers from themanner in which shaft 86 operates control arms 100, when the controlarms 100 or 100a are rotated about the central axis of the shaft 86, theoperation of their connected individual connecting means 19 is exactlythe same and therefore the operation of a connecting means 19 operatedunder those conditions will now be described.

An individual connecting means 19 which is connected to a control arm100 (or a control arm 100a) may comprise a yieldable rod assembly 114connected on one end 116 to a control arm. The other end of rod assembly114 is numbered 112 and is shown connected to a second floating link106. The floating link 106 is connected to piston 108 of the secondarycontrol valve 104. A foot 132 is pivotally connected to the secondfloating link 106 intermediate the end portions of the link. Foot 132 isslidably mounted in a support 133. The foot is urged by a spring 137against a projection 134 carried on a sheave 136. Spring 137 may bedispensed with if, for example, the foot 132 is made heavy enough tomaintain the foot against the projection so the floating link 106 willrotate about rather than lift the foot. The sheave 136 is fixed to atubular shaft 138. The sheave 136 and shaft 138 are carried by a bar 139supported at 140. In an installation having six nozzles, bar 139 willsupport six tubular shafts and six sheaves (only one of each of thoseparts being shown in Fig. 3). A cable 142 is attached to sheave 136 andthe cable passes over pulleys 144 and is jonied at 145 to a projection146 extending from the needle 12. Another cable 142a is connected tosheave 136 and carries a weight 152 that is secured to the free end ofthe cable 142a to rotate sheave 136 to take up slack in cable 142. Whena needle 12 is moved, the sheave 136 and shaft 138 will be rotatedrelative to bar 139 either by cable 142 or cable 142a to move thefloating link 106 in a direction opposite to the direction that it wasmoved by a control arm 100.

The operation of a connecting means 19, assuming piston 108 in theposition shown in Fig. 3 as an initial position, now will be described.When a control arm 100 or 100a of connecting means 19 is rotated aboutshaft 86 of the speed responsive means 17, the floating link 106 will bemoved upwardly or downwardly by the yieldable rod assembly 114. Thefloating link 106 when it rotates about foot 132 will raise or lowerpiston 108 from the position shown in Fig. 3 to regulate fluid flow tothe needle servomotor 102 to move the needle 12. Movement of needle 12will move projection 146 and cause cable 142 or cable 142a to rotatesheave 136. Sheave 136 will upon rotating raise or lower foot 132 whichrests on projection 134. The raising or lowering of the foot 132 willcause the second floating link 106 to pivot about pivotal connection 112and move piston 108 of valve 104 in a direction opposite to thedirection that piston 108 was originally moved. This will move piston108 of secondary valve 104 back to the position shown in Fig. 3 and stopthe flow of fluid to servomotor 102 and stop movement of needle 12.

Adjustable limit means 154 is provided to cooperate with the yieldablerod assembly 114 to limit the maximum opening of any nozzle and stillpermit the speed responsive means 17 to control the opening size ofother nozzles. The manner in which such limiting action is accomplishedis completely described in my copending application Serial No. 598,121,filed July 16, 1956, and entitled Control for Multijet Impulse Turbine.

As stated earlier, the present invention provides for the operation ofthe turbine runner 4 by a single nozzle when no load is imposed uponturbine 4. To accomplish this, one of the control arms, namely arm 100a,is of a special design differing from the other control arms 100.Whereas control arms 100 are secured directly to the shaft 86 to rotatewith the shaft, control arm 100a is difierent in that it is indirectlyconnected to shaft 86 through a flexible connection. The flexibleconnection comprises a lever 200 keyed to shaft 86 and a pin 201 thatconnects lever 200 to arm 100a. When turbine 4 is operating under load,it is desired that control arm 100a operate in exactly the same way thatthe control arms 100 (that are fixed to shaft 86) operate. To accomplishthis, arm 100a is provided with a bearing surface 202 a portion of whichengages the external surface of shaft 86 and biasing means, shown as aspring 205, urges bearing surface 202 into contact with shaft 86. Withthe various parts of the system in the position shown in Fig. 3,rotation of shaft 86 will move arm 100a just as though arm 100a werefixed to shaft 86 in the same manner as the arms 100.

Adjusting means (identified generally by the number 210) are provided tolimit movement of control arm 100a in a clockwise direction around shaft86 and thereby limit the minimum size opening of the nozzle connected tocontrol arm 100a. Thus adjusting means 210 operate to limit the minimumopening of nozzle 10 and limit means 154 limits the maximum opening ofnozzle 10. It will also appear as the description of the adjusting means210 proceeds that there is provided a way for moving control arm 100acontrary to the influence of the biasing spring '205 and independentlyof the influence of the speed responsive means 17.

The adjusting means 210 comprises a rod 211 extending through an opening212 in the control arm 100a. The opening 212 is provided on the oppositeside of shaft 86 with regard to the connection 116 of the adjustingmeans 19. The lower end of rod 212 is threaded to receive a threadedstop member 213. Upward motion of rod 211 will bring the stop member 213into contact with the control arm 100a and further upward movement ofthe rod 211 will lift bearing surface 202 up and off of shaft 86 androtate control arm 100a in a counterclockwise direction about pin 201.The position of stop member 213 on the lower end of rod 211 provides alost motion connection between rod 211 and stop member 213. Thus theposition of stop member 213 of the lower end of rod 211 can be adjustedto vary the upward movement required of rod 211 before engagement ismade with control arm 100a and also to vary the amount of clockwiserotation of control arm 100a under the influence of the biasing means205.

The means provided for imparting an upward movement to shaft 211 fromthe position shown in Fig. 3 to a position where stop 213 will engagearm a, is disclosed in Fig. 3 as being a solenoid 215. An energizingcircuit 216 is provided to operate the solenoid 215 to lift rod 211.Energizing circuit 216 may be connected at 217 to an energizing sourcecontrolled by a switch or other control equipment not shown. However, itis intended that circuit 216 should be continuously energized whetherthe generator 7 is carrying a load or being operated under no loadconditions. Further, it is intended that circuit 216 should bedeenergized at 217 only upon complete shutdown of generator 7 andturbine 4.

Despite the fact that circuit 216 will be deenergized at 217 only uponcomplete shutdown of generator 7 and turbine 4, switch means 218 areprovided to at other times interrupt circuit 216 and deactivate solenoid215. The switch means 218 are shown connected to a circuit breaker 219that is operable to connect or disconnect generator circuit 221 to anelectrical distribution network 222. Circuit breaker 219 is connected toswitch 218 so that the closing of circuit breaker 219 to connectgenerator circuit 221 to distribution network 222 automatically opensswitch 218 to interrupt circuit 216 and deenergize solenoid 215.Conversely, when circuit breaker 219 is open, either because generator 7has not yet been brought up to synchronous speed in preparation forconnection to network 222 or because circuit breaker 219 has been openedin preparation to shutdown of generator 7, switch 218 will then beclosed and circuit 216 energized to actuate solenoid 215.

Before describing the action that takes place upon the action ofsolenoid 215 to lift rod 211 it is believed advisable to review theoperation of the control system generally and the manner in which othercontrol arms 100 and 100a will operate their respective nozzles.

The operation of individual components of the system has been described,i.e., governor 21, control means 23, primary power device 73, secondarypower device 18 and connecting means 19. The turbine controlling systemwith reference to the speed responsive means 17, connecting means 19 andsecondary power devices 18 for operating the nozzles 10 operates as acomplete system in the following manner. For adjustment of nozzleopenings, the speed responsive means 17 amplifies the force provided bythe governor arrangement 21 through the primary power device 73 andapplies the resulting amplified force to operate the control means 23which modify the movement caused by the governor arrangement to transmitmovement of the correct amount for adjusting the nozzles. Even with thepower amplification provided by the primary power device 73 theresulting movement while powerful enough to move the connecting means 19is not powerful enough to move the needles 12. There fore the individualsecondary power devices 18 and in particular the servomotor 102 are themeans for moving each needle.

As shown in Fig. 3 decreasing turbine speed, that requires greaternozzle openings to restore operation to synchronous speed, results inthe governor 21 operating the primary power device 73to rotate shaft 86in a counterclockwise direction. The connecting arms 100 and 100a of theconnecting means 19 then move each rod assembly 114 in a downwardlydirection, floating link 106 about foot 132 to lift valve element 108 toport fluid to the servomotor 102 to move needle 12 in an openingdirection and cause the nozzles to emit sufficient additional fluid tobring the speed of turbine 4 back up to the desired speed. Similarly anincrease in turbine speed over the synchronous speed results in thegovernor 21 through primary power device 73, rotating shaft 86 in aclockwise direction. Clockwise rotation of shaft 86 causes control arms100 and 100a to move upwardly. This upward movement of the control armslifts rod assemblies 114 and pivots link 106 counterclockwise about foot132 and lowers valve element 108 to port fluid to servomotor 102 to moveneedle 12 in a nozzle closing direction. As the nozzle then closes, lesswater impinges upon turbine wheel 4 and the speed is reduced.

The manner in which adjusting means 210 operate to modify thehereinbefore described operation will now be described. With the nozzlein an open position as shown in Fig. 3, and circuit breakers 219 closedas shown in the solid lines, thereby connecting generator 7 todistribution network 222, turbine 4 and generator 7 will be operatingunder load and the operation will be as hereinbefore described. If,however, it is then desired to disconnect generator 7 from thedistribution network 222, circuit breaker 219 is opened to the positionshown in dotted lines. The opening of circuit breakcr 219 operatesswitch 218 to close circuit 216 and activate solenoid 215 to lift rod211. When circuit breaker 219 opens and load is removed from generator 7turbine 4 will then turn faster because the turbine is then turningwithout the resistance of the load applied to generator 7. This increasein turbine speed will cause the governor arrangement 21 to act to causethe primary power device 73 to rotate shaft 86 clockwise to begin toclose nozzles 10 and to slow down turbine 4 to its desired speed. Rapidcontrol of the jets will have been accomplished by the operation of thedeflector system (i.e., because of the rotation of shaft 40) to move thedeflectors 16 into the path of the jets. The entire system will continueto operate to transfer control back to the nozzles and withdraw thedeflectors. The clockwise rotation of shaft 86 will not be transmittedto control arm 100a in the same manner that it is to arms 100 becausearm 100a will be engaged with stop 21% and arm 108a will no longerrotate about the axis of shaft 86 in the same manner that arms 100 aremoving. Clockwise rotation of shaft 86 will now rotate lever 100a aboutstop 213 rather than the axis of shaft 86. The nozzle connected to arm100a will then partially close but much more slowly than the nozzlesconnected to arms 100. And with stop 213 moved up, the nozzle connectedto arm 100a cannot completely close. Stated another way, the nozzlesconnected to arms 100 will be completely closed leaving the nozzleconnected to arm 1000 still open to operate the turbine at no load.Synchronous speed will be maintained or achieved by the governor 21 thenacting only to adjust the nozzle connected to arm 100a. The amount ofclockwise rotation of arm 100a or upward movement of rod 211 before stopmember 213 and arm 10% engage can be adjusted by turning member 213 onthe threaded portion of the shaft rod 211.

With the turbine now running under no load conditions and all of thenozzles closed except the nozzle connected to control arm 100a, thisnozzle that remains open will be open sufficiently so that it will noteasily clog as the result of foreign material in the water.

With the turbine stopped or running under no load conditions, if it isagain desired to connect the generator 7 to the distribution network222, the turbine is started and/or permitted to operate at the speedrequired to synchronize the frequency of the current supplied bygenerator 7 with the requirements of the distribution network 222. Withthe turbine running at synchronous speed with one nozzle open and theremaining nozzles closed, circuit breaker 219 may then be closed toconnect generator circuit 221 to the distribution network. Closingcircuit breaker 219 automatically opens switch 218 and deenergizessolenoid 215 permitting rod 211 to return to its lowest position. Whenstop member 213 moves downwardly, spring 205 will bias control arm 100ato move clockwise about pin 201 to seat bearing surface 202 on shaft 86and line up arm 100a with arms 100. For a brief instant, clockwiserotation of control arm 100a which tends to close its connected needle,is the opposite of what is required for the turbine to carry the load ofthe network 222 at synchronous speed. However, the closing of the nozzleconnected to control arm a and increased load will cause the governorarrangement 21 to rotate shaft 86 in a counterclockwise direction,opening those needles connected to control arms 100 and once again movearm 100a counterclockwise about the axis of shaft 86 just as thegovernor would move arm 100a if it were fixed to shaft 86 like the arms100.

The control system that has been described provides a simple arrangementto control a number of nozzles. This system provides for automaticallyshifting from, for example, six nozzle operation to one nozzle operationwhen load is taken from the turbine and it begins to operate under noload conditions. This insures that the one nozzle operating the turbineat no load under governor control will be open wide enough so thatforeign matter in the water will not clog the nozzle. Furthermore, assoon as the turbine begins to again operate under load the systemautomatically shifts back to operation by all nozzles and therebyrestores the increased efliciency and power generation of multijetoperation.

Although but a single embodiment of the present invention has beenillustrated and described, it will be apparent to one skilled in the artthat various changes and modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims. Furthermore, it will be apparent from the appendedclaims that various features of the present invention can be takensingly or in combination and applied to other embodiments withoutsacrificing all of the advantages of the invention.

What is claimed is:

1. In a control system, speed responsive means, a plurality of powerdevices, individual means connecting each power device and said speedresponsive means, said speed responsive means moving said individualconnecting means through a range of movements to operate said powerdevices between first and second limit positions, selected of saidconnecting means connected to selected power devices including anadjustable device biased to maintain the same operative relationshipbetween said speed responsive means and said selected power devices asexists between said speed responsive means and all other of said powerdevices, and adjusting means connected to said adjustable device toadjust said adjustable device to limit movement of said selectedconnecting means in the direction that moves the connected power devicetoward said second limit position, and said adjusting means beingoperable to adjust said adjustable device to move said one connectingmeans contrary to the bias of said adjustable device and independentlyof the influence of said speed responsive means.

2. In a control system, speed responsive means, a plurality of powerdevices, individual means connecting each power device and said speedresponsive means, said speed responsive means moving said individualconnecting means through a range of movements to operate said powerdevices between first and second limit positions, selected of saidconnecting means connected to selected power devices including anadjustable device biased to maintain the same operative relationshipbetween said speed responsive means and said selected power devices asexists between said speed responsive means and all other power devices,and adjusting means responsive to a load carrying requirement imposedupon said power devices, said adjusting means connected to saidadjustable device to adjust said adjustable device to limit movement ofsaid selected connecting means in the direction that moves the connectedpower device toward said second limit position, and said adjusting meansbeing operable to adjust said adjustable device to move said oneconnecting means contrary to the bias of said adjustable device andindependently of the influence of said speed responsive means,

3. In a control system, speed responsive means, a plurality of powerdevices, individual means connecting each power device and said speedresponsive means, said speed responsive means moving said individualconnecting means through a range of movements to operate said powerdevices between first and second limit positions, one of said connectingmeans connected to one of said power devices including an adjustabledevice biased to maintain the same operative relationship between saidspeed responsive means and said one power device as exists between saidspeed responsive means and all other of said power devices, andadjusting means connected to said adjustable device to adjust saidadjustable device to limit movement of said one connecting means in thedirection that moves the connected power device toward said second limitposition, and said adjusting means being operable to adjust saidadjustable device to move said one connecting means contrary to the biasof said adjustable device and independently of the influence of saidspeed responsive means.

4. In a control system, speed responsive means, a plurality of nozzles,individual means connecting each nozzle and said speed responsive means,said speed responsive means moving said individual connecting meansthrough a range of movements to operate said nozzles between open andclosed positions, one of said connecting means connected to one of saidnozzles including an adjustable device biased to maintain the sameoperative relationship between said speed responsive means and said onenozzle as exists between said speed responsive means and all other ofsaid nozzles, and adjusting means connected to said adjustable device toadjust said adjustable device to limit movement of said one connectingmeans in the direction that moves the connected nozzle toward saidclosed position, and said adjusting means being operable to adjust saidadjustable device to move said one connecting means contrary to the biasof said adjustable device and independently of the influence of saidspeed responsive means.

5. An electrical generating apparatus comprising: an electricalgenerator, an impulse hydraulic turbine connected to said generator; anda system connected to said apparatus for controlling said turbine tooperate said generator at a substantially constant speed, said controlsystem comprising; speed responsive means, a plurality of nozzles fordirecting jets of fluid to impinge upon and rotate said turbine nozzleand said speed responsive means, said speed responsive means moving saidindividual connecting means through a range of movements to operate saidnozzles between open and closed positions, one of said connecting meansconnected to one of said nozzles including an adjustable device biasedto maintain the same operative relationship between said speedresponsive means and said one nozzle as exists between said speedresponsive means and all other of said nozzles, and adjusting meansresponsive to a load carrying requirement imposed upon said generator,said adjusting means connected to said adjustable device to adjust saidadjustable device to limit movement of said one connecting means in thedirection that moves the connected nozzle toward said closed position,said adjusting means being operable to adjust said adjustable device tomove said one connecting means contrary to the bias of said adjustabledevice and independently of the influence of said speed responsivemeans.

6. An electrical generating apparatus comprising: an electricalgenerator, an impulse hydraulic turbine connected to said generator;circuit means connected to said generator and including circuit openingand closing means for connecting and disconnecting said generator to adistribution network; and a control system connected to said 10apparatus for controlling said turbine to operate said generator at asubstantially constant speed, said control system comprising; speedresponsive means, a plurality of nozzles for directing jets of fluid toimpinge upon and rotate said turbine nozzle and said speed responsivemeans, said speed responsive means moving said individual connectingmeans through a range of movements to operate said nozzles between openand closed positions, one of said connecting means connected to one ofsaid nozzles including an adjustable device biased to maintain the sameoperative relationship between said speed responsive means and said onenozzle as exists between said speed responsive means and all othernozzles, and adjusting means connected to said circuit opening andclosing means responsive to opening action of said opening and closingmeans to limit movement of said one connecting means in the directionthat moves the connected nozzle toward said closed position, saidadjusting means being operable to adjust said adjustable device toprovide for moving said one connecting means in the direction that movesthe connected nozzle toward said open position against the bias of saidadjustable device and independently of the influence of said speedresponsive means.

7. An electrical generating apparatus comprising: an electricalgenerator, an impulse hydraulic turbine connected to said generator;circuit means connected to said generator and including circuit openingand closing means for connecting and disconnecting said generator to adistribution network; and a control system connected to said apparatusfor controlling said turbine to operate said generator at asubstantially constant speed, said control system comprising; speedresponsive means, a plurality of nozzles for directing jets of fluid toimpinge upon and rotate said turbine nozzle and said speed responsivemeans, said speed responsive means moving said individual connectingmeans through a range of movements to operate said nozzles between openand closed positions, one of said connecting means connected to one ofsaid nozzles including an adjustable device biased to maintain the sameoperative relationship between said speed responsive means and said onenozzle as exists between said speed responsive means and all othernozzles, and solenoid operated adjusting means connected to said oneconnecting means, an energizing circuit connected to said solenoidoperated means, said energizing circuit including a switch connected tosaid circuit opening and closing means, said switch closing saidenergizing circuit upon opening action of said opening and closing meansto limit movement of said one connecting means in the direction thatmoves the connected nozzle toward said closed position, said adjustingmeans being operable to adjust said adjustable device to provide formoving said one connecting means in the direction that moves theconnected nozzle toward said open position against the bias of saidadjustable device and independently of the influence of said speedresponsive means.

References Cited in the file of this patent UNITED STATES PATENTS533,004 Doolittle Ian. 22, 1895 549,848 Doolittle Nov. 12, 18951,994,121 Collingham Mar. 12, 1935 2,076,588 Pearson Apr. 13, 19372,365,905 Rheingaus Dec. 26, 1944 2,491,059 Ring Dec. 13, 1949 2,635,847Rued Apr. 21, 1953 FOREIGN PATENTS 279,854 Germany Oct. 30, 1914

